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Biomedical subjects

T Nakabayashi

Publications and source records attributed to T Nakabayashi.

At least 109 records · Page 6Linked to original sources

Toxoplasma gondii: antigenic differences between endozoites and cystozoites defined by monoclonal antibodies.

The antigenic differences between endozoites and cystozoites of Toxoplasma gondii were analyzed by indirect immunofluorescent assay and Western blotting using monoclonal antibodies. An antigenic determinant of an antigen of 20 kDa mol. wt. that appeared to be localized in the cytoplasm was observed to be specific to cystozoites alone. The 20-kDa antigen was diffused throughout the parasite and was observed in cystozoites produced both in vivo and in vitro.

Animals↗

Plasmodium falciparum: characterization of a 33-kDa soluble antigen.

A 33-kDa soluble antigen identified in the culture supernatant by patient serum and monoclonal antibodies was present in rings, trophozoites, schizonts, and merozoites of Plasmodium falciparum. The antigen which is released into the culture supernatant by growing parasites was also observed in the host cells of trophozoites and schizonts and could be localized on the host cell surface. Its specificity for the surface of trophozoites and schizonts was observed to decrease with increased duration without subculture. The antigen could then be detected on the surface of noninfected erythrocytes. The antigenicity of the 33-kDa antigen was destroyed by heating at 65 degrees C. Monoclonal and polyclonal specific antibodies weakly inhibited parasite growth in vitro. The antigen was present in both knob positive and knob negative parasites in all the P. falciparum isolates tested.

Animals↗

Release of PI-anchoring enzymes and other effects of phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis on TN-368 cells from a moth ovary.

Release of PI-anchoring enzymes and other effects of phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis on TN-368 cells from a moth ovary. Toxicon 27, 637-645, 1989.--The effect of phosphatidylinositol-specific phospholipase C(PIPLC) from Bacillus thuringiensis was investigated on TN-368 cells, derived from the ovary of a moth, Trichoplusia ni. Quantitative analysis of lipids showed that phosphatidylinositol (PI) was contained as one of the major phospholipids in TN-368 cells, whereas sphingomyelin and cholesterol were minor lipid components. When TN-368 cells were treated with PIPLC, significant amounts of alkaline phosphatase, 5'-nucleotidase and beta-glucosidase were released from these cells. Thus, these enzymes were shown to be PI-anchoring proteins in the plasma membrane of these cells. In the presence of 4.2 units of PIPLC, the cell growth of TN-368 was inhibited by 50%. In contrast with normal cells, the cells cultured in the presence of PIPLC became swollen and globular, losing their protoplasmic extensions. Also, there was degeneration of the interior of TN-368 cells cultivated in the presence of PIPLC. Mitochondria became swollen with a decrease in number of granules while the crista turned transparent. Also, an increase in lysosomes was observed and vacuoles seemingly derived from smooth endoplasmic reticula appeared.

Animals↗

Generation of monoclonal anti-dermatan sulphate antibodies cross-reacting to calf thymus DNA.

Monoclonal anti-dermatan sulphate antibodies were produced with hybridization after immunizing BALB/c mice with dermatan sulphate (DS). These antibodies were tested for cross-reactivity to double-stranded DNA (dsDNA) and heat-denatured DNA (ssDNA). Five clones had binding activity to DS, dsDNA and ssDNA in enzyme-linked immunosorbent assay, but no clones binding to DS alone were produced. Two (2H8 and 3C4) of the five clones were selected for analysis. Their binding activity to DS, ssDNA and dsDNA were inhibited by DS, dsDNA and ssDNA. DNase I treatment abolished the binding activity to dsDNA and ssDNA, completely, but had no effect on the binding activity to DS. On the other hand, chondroitinase ABC treatment of the solid-phased DS augmented the binding to DS. The inhibition assay using digested fractions suggested that the epitope recognized by 2H8 and 3C4 clones could not be in delta Di-4S or delta Di-diSB but in the linkage regions of DS.

Animals↗

Isolation and characterization of chicken liver lysosomes.

The distribution patterns of chicken liver lysosomal enzymes were studied in iso-osmotic gradients of Percoll. The lysosomal enzymes separated by Percoll gradients showed three different types of distribution. In contrast with rat liver lysosomes, purified chicken liver lysosomes were very stable during storage at 4 degrees C.

Acetylglucosaminidase↗

[Successful treatment of cerebral cysticercosis with praziquantel].

A case of a 56-year-old Korean man with cerebral cysticercosis was reported. This case demonstrated the first successful treatment with praziquantel in Japan and also the usefulness of a low-dose regime in the treatment of cerebral cysticercosis. The patient was admitted to our hospital with a 7 years history of generalized seizure and a 6 months history of gait disturbance. He had 6 subcutaneous nodules. A CT scan of the brain showed multiple cysts containing a small calcification and the largest lesion measured 5 cm in diameter in the cerebellar vermis. Posterior fossa craniectomy was performed and the cyst was pathologically confirmed as cysticercosis. A month postoperatively the patient was given praziquantel 50 mg/kg body weight in 3 divided doses per day. But medication with praziquantel was stopped on the 5th day because of severe headache, nausea and vomiting. He was readmitted 6 months later with appearance of gait disturbance, left facial paresis and dysphagia. A CT scan revealed enlargement of some of the residual cysts. The patient was then given smaller doses of praziquantel 8 mg/kg body weight in 3 divided doses with steroid cover for 48 days. He experienced no side effect during the therapy and became free from the neurological symptoms. A CT scan showed complete disappearance and only numerous small calcifications of the cysts.

Brain Diseases↗

Modification of growth rate of Toxoplasma gondii by continuous passage in immune mice.

Growth of the RH strain of Toxoplasma gondii, is suppressed in mice immunized with Toxoplasma antigens. At the second passage, the growth of T. gondii harvested from immune mice is suppressed more strongly in immune mice than that of T. gondii from control mice. After 52 passages in immune mice, the growth of T. gondii was still suppressed in immune mice than in control mice. T. gondii did not possess ability of antigenic variation (Pfefferkorn et al., 1983). After vaccination with the S-273 strain of T. gondii, mice were challenged twice with the RH strain. Cysts in brains caused death of all mice by inoculation at the 1st, 2nd, 3rd, 4th and 8th week after the second challenge of the RH strain. But the cysts from mice at the 16th and 30th week have decreased virulence, causing death in only 2 out of 4 and 1 out of 4 mice, respectively. Virulence of cysts had no definite relationship to Toxoplasma antibodies by indirect latex agglutination test and the numbers of cysts per brain. Growth variation of T. gondii is proposed under unfavourable conditions as in mice immunized with Toxoplasma antigens or vaccinated with the S-273 strain.

Animals↗

Clinical evaluation of antimalarial regimens in Japan.

The actual situation of the treatment of malaria for the past 10 years in Japan was investigated and analyzed. As a result, it was revealed that there were not a few cases which had been treated improperly probably because of the difficulty of getting antimalarial agents. Moreover, it was made clear that the death rate on falciparum malaria was constantly high, 8.7%, as expected and the relapse rate of vivax malaria was still as high as 18.0%. There was the recrudescence of falciparum malaria at 8.1%, maybe because of the influence of the prevalence of the drug-resistant strains of Plasmodium falciparum. The trouble in getting antimalarial agents has been overcome since 1980. Study Group on Pharmacotherapy of Imported Tropical Diseases was organized by the Ministry of Health and Welfare in 1980, and antimalarial agents have been supplied free of charge through the Study Group for the treatment of the disease. The number of cases of imported malaria has increased in our country. There are a lot of problems to be solved quickly to cope with the situation: people who travel abroad should be enlightened on the danger of the infection of malaria and take prophylactics for the disease and physicians should get familiar with the disease being supplied with information about it.

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